1. Field of the Invention
This invention relates to conveyors and drive mechanisms for conveyors, and more particularly to a padded chain for conveying articles or driving rollers in a conveying system such as an accumulation conveyor.
2. Related Art
Over the yeas, various combinations of chain and rubber or plastic pads or belts have been devised and used to drive the rollers in a roller conveyor. These devices include a chain drive wherein a pad or high friction member is a continuous band, similar to a belt, mounted to the chain links wherein the links are positioned horizontally with respect to the conveyor rollers as in U.S. Pat. No. 5,176,246 to Wiggers et al. They also include devices where an elastic belt is mounted to a chain wherein the chain rollers are parallel to the rollers of a conveyor as in U.S. Pat. No. 4,074,085 to Bodewes. It is also known to use individual pads, one of which is mounted on each link of the chain as disclosed, for example, in U.S. Pat. No. 4,458,809 to White et al., and U.S. Pat. No. 5,906,267 to Heit et al.
One of the limitations of devices such as the horizontal continuous belt of the Wiggers et al. patent or roller mounted pads as in the Bodewes and White et al. patents is that the chain is incapable of a reverse wrap. Consequently, the drive chain can only effectively move the rollers in a single direction.
A known solution to the "reverse wrap" problem is found in padded chains wherein individual pads are mounted exterior of and parallel to the links. An example of this construction is shown in FIGS. 1 and 2, illustrating a padded conveyor drive chain 60 manufactured by Rapid Industries. The drive chain 60 comprises a plurality of interconnected conventional links 62. An elastomeric pad 64 is mounted on each side of the chain 60 on consecutive links 62 by pins 66 extending laterally through the links 62, securing the pads 64 by an external link-shaped washer 68. Each pad 64 is roughly trapezoidal shaped, thereby enabling the chain 60 to wrap in both directions.
One of the limitations of the padded chain of FIGS. 1 and 2 is that spaces exist between the respective pads 64, generating significant noise and uneven motion as the chain 60 interacts with the rollers 50 as part of the chain conveyor 10, 12, 14. They also may not provide adequate "gripping" if the chain were to be used as a conveyor itself, moving articles requiring special handling such as furniture or appliances.
These and other limitations of known padded chain conveyors remain significant problems in the industry.